#include<bits/stdc++.h>
#include<omp.h>
using namespace std;
#define int long long
#define rep(i,n) for(int i=0;i<n;++i)
#define rep1(i,n) for(int i=1;i<=n;++i)
#define reps(i,a,b) for(int i=a;i<b;++i)
#define repnega(i,a,b) for(int i=b;i>a;i--)
#define mod 1000000007
#define endl '\n'
#define AC ios_base::sync_with_stdio(false);cin.tie(0);
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

int dp[109][20009];
signed main(){
    int n,m,k;
    cin>>n>>m>>k;
    rep(i,n)m-=k*i;
    if(m<0){
        cout<<0<<endl;
        return 0;
    }
    dp[0][0]=1;
    rep1(i,n)rep(j,m+1){
        if(j-i>=0){
            dp[i][j]=(dp[i-1][j]+dp[i][j-i])%mod;
        }else{
            dp[i][j]=dp[i-1][j];
        }
    }
    cout<<dp[n][m]<<endl;
}